It is believed that examples of known fuel injection systems use an injector to dispense a quantity of fuel that is to be combusted in an internal combustion engine. It is also believed that the quantity of fuel that is dispensed is varied in accordance with a number of engine parameters such as engine speed, engine load, engine emissions, etc.
It is believed that examples of known electronic fuel injection systems monitor at least one of the engine parameters and electrically operate the injector to dispense the fuel. It is believed that examples of known injectors use electromagnetic coils, piezoelectric elements, or magnetostrictive materials to actuate a valve.
It is believed that examples of known valves for injectors include a closure member that is movable with respect to a seat. Fuel flow through the injector is believed to be prohibited when the closure member sealingly contacts the seat, and fuel flow through the injector is believed to be permitted when the closure member is separated from the seat.
It is believed that examples of known injectors include a spring providing a force biasing the closure member toward the seat. It is also believed that this biasing force is adjustable in order to set the dynamic properties of the closure member movement with respect to the seat.
It is further believed that examples of known injectors include a filter for separating particles from the fuel flow, and include a seal at a connection of the injector to a fuel source.
It is believed that such examples of the known injectors have a number of disadvantages.
It is believed that examples of known injectors must be assembled entirely in an environment that is substantially free of contaminants. It is also believed that examples of known injectors can only be tested after final assembly has been completed.
According to the present invention, a fuel injector can comprise a plurality of modules, each of which can be independently assembled and tested. According to one embodiment of the present invention, the modules can comprise a fluid handling subassembly and an electrical subassembly. These subassemblies can be subsequently assembled to provide a fuel injector according to the present invention.
The present invention provides a fuel injector for use with an internal combustion engine. The fuel injector comprises a valve group subassembly and a coil group subassembly. The valve group subassembly includes a tube assembly having a longitudinal axis extending between a first end and a second end, the tube assembly including an inlet tube having an inlet tube face; a seat secured at the second end of the tube assembly, the seat defining an opening. An armature assembly disposed within the tube assembly, the armature assembly having a closure member disposed at one end of the armature assembly and an armature portion disposed at the other end of the armature assembly, the armature assembly having an armature face; a member biasing the armature assembly toward the seat. A filter assembly disposed within the tube assembly; an adjusting tube disposed within the tube assembly proximate the second end; a non-magnetic shell extending axially along the axis and coupled at one end of the shell to the inlet tube. A valve body coupled to the other end of the non-magnetic shell. A lift setting device disposed within the valve body. A valve seat disposed within the valve body and contiguously engaging the closure member; and a first attaching portion. The coil group subassembly includes a housing, a bobbin disposed partially within the housing, the bobbin having at least one contact portion formed thereon; a solenoid coil operable to displace the armature assembly with respect to the seat, the solenoid coil being electrically coupled to the contact terminals. At least one pre-bent terminal being electrically coupled to the contact portion; at least one overmold; and a second attaching portion fixedly connected to the first attaching portion.
The present invention also provides for a method of assembling a fuel injector. The method comprises providing a valve group subassembly and a coil group subassembly, inserting the valve group subassembly into the coil group subassembly, aligning the valve group subassembly relative to the coil group subassembly and affixing the two subassemblies. The valve group subassembly includes a tube assembly having a longitudinal axis extending between a first end and a second end, the tube assembly including an inlet tube having an inlet tube face; a seat secured at the second end of the tube assembly, the seat defining an opening; an armature assembly disposed within the tube assembly, the armature assembly having a closure member disposed at one end of the armature assembly and an armature portion disposed at the other end of the armature assembly, the armature assembly having an armature face; a member biasing the armature assembly toward the seat; a filter assembly disposed within the tube assembly; an adjusting tube disposed within the tube assembly proximate the second end; a non-magnetic shell extending axially along the axis and coupled at one end of the shell to the inlet tube; a valve body coupled to the other end of the non-magnetic shell; a lift setting device disposed within the valve body; a valve seat disposed within the valve body and contiguously engaging the closure member; and a first attaching portion. The coil group subassembly includes a housing; a bobbin disposed partially within the housing, the bobbin having at least one contact portion formed thereon; a solenoid coil operable to displace the armature assembly with respect to the seat, the solenoid coil being electrically coupled to the contact terminals; at least one pre-bent terminal electrically coupled to the contact portion; and at least one overmold.
The present invention also provides yet another method of assembling a modular fuel injector. The method comprises providing a valve group subassembly and a coil group subassembly, inserting the valve group subassembly into the coil group subassembly, aligning the valve group subassembly relative to the coil group subassembly and affixing the two subassemblies. The valve group subassembly includes a tube assembly having a longitudinal axis extending between a first end and a second end, the tube assembly including an inlet tube having an inlet tube face; a seat secured at the second end of the tube assembly, the seat defining an opening; an armature assembly disposed within the tube assembly, the armature assembly having a closure member disposed at one end of the armature assembly and an armature portion disposed at the other end of the armature assembly, the armature assembly having an armature face; a member biasing the armature assembly toward the seat; a filter assembly disposed within the tube assembly; an adjusting tube disposed within the tube assembly proximate the second end; a non-magnetic shell extending axially along the axis and coupled at one end of the shell to the inlet tube; a valve body coupled to the other end of the non-magnetic shell; a lift setting device disposed within the valve body; a valve seat disposed within the valve body and contiguously engaging the closure member; and a first attaching portion. The coil group subassembly includes a housing; a bobbin disposed partially within the housing, the bobbin having at least one contact portion formed thereon; a solenoid coil operable to displace the armature assembly with respect to the seat, the solenoid coil being electrically coupled to the contact terminals; at least one pre-bent terminal electrically coupled to the contact portion; and at least one overmold. The providing of the coil group or the power group further includes providing a clean room, fabricating the valve group in the clean room that comprises between 52 to 62 percent of a predetermined number of operations to assemble a ready-to-be shipped modular fuel injector, testing at least one of the valve group subassembly and coil group subassembly that comprises between 3 to 13 percent of the predetermined number of operations, performing welding operations on at least one of the valve group and coil group subassemblies that comprises between 3 to 8 percent of the predetermined number of operations, performing machine screw operations and machining operations on at least one of the valve group and the coil group subassemblies that comprise between 3 to 9 percent of the predetermined number of operations. At least one of the providing of the coil group subassembly and the assembling of the valve group and the coil group subassemblies can be performed, either inside or outside of the clean room, that comprises between 12 to 22 percent of the predetermined number of operations.
The present invention also provides method of manufacturing a fuel injector by providing a clean room, fabricating a fuel tube assembly, an armature assembly and fabricating a seat assembly in the clean room, assembling a fuel group by inserting an adjusting tube into the fuel tube assembly; inserting a biasing element into the fuel tube assembly; inserting the armature assembly into the fuel tube assembly; connecting the seat assembly to the fuel tube assembly; and inserting the fuel group into a power group outside the clean room.
The present invention further provides a method of assembling a fuel injector by providing a clean room, fabricating a fuel tube assembly, an armature assembly and a seat assembly in the clean room; assembling the fuel group by inserting an adjusting tube into the fuel tube assembly; inserting a biasing element into the fuel tube assembly; inserting the armature assembly into the fuel tube assembly; and connecting the seat assembly to the fuel tube assembly.
The present invention additionally provides for a method of manufacturing a modular fuel injector. The method comprises providing a clean room, manufacturing a sealed fuel injector unit via a predetermined number of operations by fabricating a fuel group in the clean room; testing the fuel injector including testing the fuel group and a power group; performing welding operations on at least one of the fuel group and power group; machining and performing screw machine operations on at least one of the fuel group and power group; and assembling the fuel group with a power group outside the clean room into a sealed modular fuel injector unit. Each of the fabricating, testing, performing, machining and assembling operation comprises, respectively, a specified range of the predetermined number of operations.
The present invention provides yet another method of assembling a modular fuel injector. The method comprises providing a clean room, assembling a ready-to-deliver modular fuel injector unit by a predetermined number of assembling operations. The assembling operations include fabricating a fuel group in the clean room that comprises between 52 to 62 percent of the predetermined number of operations; testing the fuel injector including testing the fuel group and a power group that comprises between 3 to 13 percent of the predetermined number of operations; performing welding operations on at least one of the fuel group and power group that comprise between 3 to 8 percent of the predetermined number of operations; machining and performing machine screw operations on at least one of the fuel group and power group that comprise between 3 to 9 percent of the predetermined number of operations; and assembling the fuel group with a power group outside the clean room into a ready-to-deliver modular fuel injector unit that comprises between 12 to 22 percent of the predetermined number of operations.
The present invention further provides a method of setting armature lift in a fuel injector. The method comprises providing a tube assembly, providing a seat assembly having a seating surface, connecting the seat assembly to the second valve body end, and adjusting the distance between the first tube assembly end and the seating surface. The tube assembly includes an inlet tube assembly having a first tube assembly end; a non-magnetic shell having a first shell end and a second shell end, the first shell end being connected to the first tube assembly end; and a valve body having a first valve body end and a second valve body end, the first valve body end being connected to the second shell end.
The present invention additionally provides a method of connecting a fuel group to a power group. The method includes providing a fuel tube assembly having a longitudinal axis extending therethrough; installing an orifice plate on the fuel tube assembly, rotating the power group relative to the fuel group such that the at least one opening is disposed a predetermined angle from the power connector relative to the longitudinal axis; installing the fuel group in a power group; and fixedly connecting the fuel group to the power group. The orifice plate having at least one opening disposed away from the longitudinal axis. The power group includes a generally axially extending dielectric overmold and a power connector extending generally radially therefrom.
The present invention further provides a method of connecting a fuel group to a power group in a fuel injector. The method includes manufacturing a fuel group. The manufacturing includes providing a fuel tube assembly having a longitudinal axis extending therethrough; installing an orifice plate on the fuel tube assembly, the orifice plate having at least one opening disposed away from the longitudinal axis. The method further comprises providing a power group having a generally axially extending dielectric overmold and a power connector extending generally radially therefrom; rotating the power group relative to the fuel group such that the at least one opening is disposed a predetermined angle from the power connector relative to the longitudinal axis. After the power group is rotated, installing the fuel group in the power group, and fixedly connecting the fuel group to the power group.